Leafcurl Ash, Woolly Apple and Woolly Beech Aphids

    Leafcurl Ash Aphid, Woolly Apple Aphid and Woolly Beech Aphid

    Prociphilus fraxinifolii; Eriosoma lanigerum; Phyllaphis fagi

    leafcurl ash aphids

    Leafcurl ash aphids and damage (James Solomon, USDA Forest Service, Bugwood.org)

    woolly apple aphids

    Left: Woolly apple aphid colony (Whitney Cranshaw, Colorado State University, Bugwood.org); Right: Long-term damage to apple tree (H. J. Larsen, Bugwood.org)

    woolly beech aphids

    Woolly beech aphids and damage (Louis-Michel Nageleisen, Department of Forest Health, Bugwood.org)

    Pest Description

    • small, ~ 1/8 inch; pear shaped; color variable depending on species
    • bodies covered in a white, waxy filament that gives a cottony or woolly appearance (more apparent on some species than others)

    Host Plants, Diet & Damage

    • cotoneaster, hawthorn, beech, ash, crabapple, firethorn, elm, etc.
    • attack roots, trunks, limbs, leaves and shoots
    • white, waxy substance can build up on plants
    • some species curl, twist, or cup leaves or feed on roots
    • honeydew or sooty mold may be present

    Biology, Life Cycle & Damaging Life Stage

    • some have alternate hosts; others migrate between different parts of the same plant
    • overwinter as immatures on roots or as eggs on bark
    • emerge in spring and move up trunks to feed on leaves
    • mid-summer through fall, aphids migrate back to ash roots to overwinter
    • when aphid populations become high, winged aphids will fly to nearby hosts
    • winged adults may emerge from the roots in fall to mate

    IPM Recommendations

    • These aphids have little negative effect on tree health; tolerate pest.
    • Monitor bark, branches and undersides of leaves for aphids in the spring.
    • Waxy coating and protection from curling leaves make cover sprays less effective.
    • Apply a systemic insecticide (neonicitinoid) in the spring.